Transfer device for conveying molten metal



July 31, 1956 M. TAMA 2,756,988

TRANSFER DEVICE FOR CONVEYING MOLTEN METAL Filed Oct. 6, 1953 2 Sheets-Sheet 1 IN V EN TOR. MARlO TAMA M. TAMA 2,756,988

TRANSFER DEVICE FOR CONVEYING MOLTEZN METAL July 31, 1956 2 Sheets-Sheet 2 Filed Oct. 6, 1953 INVENTOR. MARIO TAMA United States Patent TRANSFER DEVICE FOR CONVEYING MULTEN METAL Mario Tama, Mornisville, Pa., assignor to Ajax Engineering Corporation, Trenton, N. J., a corporation of New Jersey Application October 6, 1953, Serial No. 384,406

1 Claim. (Cl. 266-38) This invention relates to an apparatus for the transfer of molten metal from one container to another, such as, for example, the transfer of molten metal from a melting furnace to a holding furnace.

In the art of casting metals it is conventional to melt a batch of metal in a melting furnace. When this furnace is filled with molten metal the latter is then transferred to a holding furnace from which the metal is distributed to the casting molds at intervals as required. The operation of transferring the metal from the melting furnace to the holding furnace is of critical importance since it is essential to prevent the formation and dispersion throughout the metal of oxides and other impurities during the transfer. In particular, it is usually necessary to avoid cascading the metal, that is, the pouring of a stream of molten metal onto another surface of molten metal. Such cascading is particularly conducive to the formation and dispersion of oxides and other impurities when the molten metal is an aluminum alloy.

As heretofore practiced before the introduction of the present invention, one of the conventional methods of avoiding the effect of cascading during the transfer of molten metal from one furnace to another has been to employ a siphon tube in which the flow of metal is initiated by a vacuum pump. This siphon tube is usually in the form of an inverted U-shaped cast iron tube of approximately five inches in diameter having opposite open ends in communication with the two furnaces be tween which the molten metal is to be transferred. The discharge end of the tube is generally placed adjacent the bottom of the receiving furnace and is maintained beneath the level of the molten metal so that the metal flowing through the tube enters the molten bath beneath the surface of the latter.

This conventional arrangement, although reducing the cascading effect, is objectionable and disadvantageous for several reasons, the most significant defect being that the metal frequently solidifies within the siphon tube, rendering the latter inoperative and resulting in expensive and time consuming breakdowns in the entire casting operation. Furthermore, the siphon tube has to be primed with the help of a vacuum pump to obtain the initial flow from one container to the other.

A primary object of the present invention is to provide an apparatus for the transfer of molten metal in such a manner as to avoid the above-noted objectionable results of either cascading the metal or employing a siphon tube or other means requiring additional equipment like a vacuum pump. That is, the apparatus of the present invention efiiciently transfers the molten metal from one furnace to another while preventing the formation and dispersion of oxides and other impurities in the molten bath due to cascading, eliminating the possibility of the flowing stream of metal solidifying within the transfer apparatus, and maintaining the latter out of contact with the molten bath when the apparatus is not actually in operation.

Another object is to provide a novel arrangement of "ice melting furnace, holding furnace, and means for transferring molten metal from the former to the latter, so as to obviate the above-noted defects present in the structures as heretofore constructed in the prior art.

Briefly described, these objects in the present invention are obtained by the use of a novel transfer funnel having a horizontally-extending trough-like portion leading from the melting furnace to the holding furnace. The melting furnace is provided with a mechanism for tilting it so as to discharge the molten metal contained therein into the trough-like portion which carries the molten stream toward the holding furnace. The transfer funnel is pro vided with a vertical tube communicating at its lower end within and adjacent the bottom of the holding furnace,

this tube serving to convey the molten stream from the trough-like portion and to discharge the molten metal beneath the surface of the molten bath within the holding furnace. When the transfer operation is completed, the transfer funnel is quickly and easily retracted to an inoperative position whereby the tube is withdrawn from the molten bath contained within the holding furnace.

Other objects and advantages of the present invention will be apparent as the description proceeds or are inherent in the structure described in this specification and shown in the appended drawing in which:

Figure l is a vertical sectional view of two melting furnaces located adjacent and at opposite sides of a holding furnace, and also applicants novel device for transferring metal from each of the melting furnaces to the holding furnace, the transfer device associated with the melting furnace at the left-hand side of the drawing being shown in the operative pouring position while the transfer device at the right being shown in its retracted inoperative position; and

Figure 2 is a top plane view of the arrangement shown in Fig. 1.

As shown in the drawings, the reference numeral 11 indicates generally a centrally-located holding furnace flanked on opposite sides by a pair of melting furnaces 12 and 13. The latter are substantially identical and only the left hand heating furnace 12 need be described in detail, although it is to be understood that the specific structural details of the furnaces 11, 12, 13 form no part of the present invention which may be practiced using other types of apparatus wherein the problem of molten metal arises.

The melting furnace 12 is disclosed for purposes of illustration as being of the induction type, there being an inductor 14 having a transformer 15 to transmit heat to the metal 16 within the enclosure formed by the refractory-lined walls 17. The upper end of the furnace 12 is closed by a cover 18. The wall 17' facing the holding furnace 11 is provided with a spout-like opening 19 extending therethrough.

The right-hand melting furnace 13 is shown in the normal upright position Whereas the left-hand melting furnace 12 is shown in a tilted position in which the molten metal pours through the spout-like opening 19. The tilting of the furnaces 12, 13 is provided by a hydraulic cylinder 20 which is conventional and well-known in the art and need not be further described.

The holding furnace 11 comprising an inductor 21 having an inductive coil 22 for heating the metal 23 within the enclosure formed by the walls 24 and the bottom 25. The furnace 11 also has a pair of transfer funnels indicated generally at 26, 27 for a purpose to be described in detail below.

Each of the transfer funnels 26, 27 comprises a trough portion 28 which in the operative position assumed by the left-hand funnel 26 extends horizontally from the adjacent melting furnace 12 toward the interior of the holding furnace 11. The trough portions 28 are refractorylined and of substantially U-shape in cross-section. The outer ends 29 of the trough 28 are located directly beneath the pouring openings or spouts 19 of the respective melting furnaces 12, 13 when the latter are in the tilted pouring position and the troughs 28 are in the horizontal position as shown by the left-hand transfer funnel 26.

The inner ends 30 of the trough 28 are each provided with a tube 31 extending vertically downward when the funnels 26, 27 are in the operative pouring position. Each tube 31 has an upper open end communicating with the interior of the respective inner end 30 of the trough 28 and a lower end 32 adjacent the bottom of the holding furnace 11. Each of the lower ends 32 of the tubes 31 is provided with a discharge nozzle or orifice 32 having a diameter smaller than that of the interior of the tube 31 whereby the molten stream may be discharged through the orifice 32 at a suitable desired velocity while the inner diameter of the tube 31 may be made large enough to prevent clogging of solidified metal therein. The outer ends 29 of the troughs 20 are closed by end walls 29 and the inner ends are similarly closed by end walls 3-0, whereby the troughs 28 form channels or conduits of substantially U-shaped cross-section and closed at their inner and outer extremities.

Each of the transfer funnels 26, 2'7 is rotatably mounted for rotation about a horizontal axis by mounting means 33 secured to the underside of each trough portion 28, said mounting means 33 being supported by the wall of furnace 11 whereby the funnels 26, 27 may be moved to either the retracted position assumed by funnel 27 or the operative pouring position assumed by funnel 26. The means for moving the funnels 26, 27 to either of these positions is not shown in the drawing and may be any conventional electrical, hydraulic or mechanical mechanism well known in the art. It is also feasible to actuate the funnels 26, 27 manually if so desired.

The operation of the apparatus will now be described. The melting furnaces 12, 13 are charged with metal which is melted by heat supplied by the inductors 14, after which either or both of the melting furnaces 12, 13 is tilted to the pouring position by the hydraulic means 20, as indicated by the tilted position assumed by the left-hand furnace 12. The molten metal 16 within the tilted melting furnace 12 is thereby caused to flow through the pouring opening or spout 19 and onto the outer end 29 of the respective trough 28 which is in the horizontal pouring position.

The molten stream of metal then flows within the trough 28 toward its inner end 30 where it enters the upper open end of the vertical tube 31. stream then fiows down within the tube 31 toward the lower open end 32 which is submerged in the molten bath 23 contained within the holding furnace 11. It will be noted that the molten stream discharges from the orifice 32 in the lower end 32 of the tube 31 and into the molten bath 23 at a point below the surface of the latter.

After the molten metal has been transferred from the melting furnace 12 to the holding furnace 11 in the manner described above, the hydraulic means 20 is actuated to return the heating furnace 12 to its normal upright position as shown by the position of the melting furnace 13 and the transfer funnel 26 is rotated about the mounting means to the retracted position shown by the transfer funnel 27. It will be seen that when the transfer funnels 26, 27 are in their retracted positions the tubes 31 are completely withdrawn from the molten bath 23 within the holding furnace 11. The latter is then tilted to pour the molten metal 23 into ingot or billet molds,

The molten this operation forming no part of the present invention.

Because the molten stream flowing down through the submerged tube 31 is discharged below the surface of the molten bath 23 contained within the holding furnace 11, the effect of cascading has been eliminated in the apparatus of the present invention. That is, the fresh metal stream is not brought into contact with another surface of molten metal, thereby eliminating the formation and dispersion of oxides and other impurities that would otherwise result.

Furthermore, the transfer funnels 26, 27 are so constructed that there is no danger of the molten stream solidifying so as to clog either their trough portions 28 or the tubes 31. The troughs 28 are open whereby they are easily accessible for maintenance. They are also of relatively large cross-section whereby considerable solidification of the molten stream does not produce any appreciable decrease in the flow rate since the molten metal can flow freely over the solidified metal in the bottom of the troughs 28. The only restricted conduit in the funnels 26, 27 is that within the tube 31. However, solidification of metal within the tubes 31 is prevented by the fact that they are almost entirely submerged in the hot bath 23 during the periods of metal transfer. Thus break-downs and repairs due to freezing of metal in the transfer apparatus have been eliminated in the present invention.

It is also to be noted that the tubes 31 are submerged in the molten bath 23 only during the brief periods of metal transfer and are normally withdrawn in the retracted position shown by the right-hand transfer funnel 27. This prevents the metal of the tube 31. from reacting with the hot molten bath 23 and thereby reduces wear and maintenance of the tube 31 and prevents contamination of the molten bath 23.

It is to be understood that the specific embodiment of the invention shown in the drawing and described in the specification is merely illustrative of one of the many forms which the invention may take in practice, the scope of the invention being delineated in the appended claim.

I claim:

A device for the transfer of molten metal from a tiltable melting furnace into a tiltable holding furnace, said device comprising a trough extending outwardly from said holding furnace and having a metal inlet and outlet end, a tube fastened at an angle of about degrees to the outlet end of said trough, and said tube having a constriction adjacent its opening at the bottom thereof, said trough being pivotally mounted on the outer wall of said holding furnace to permit tilting in any position of the holding furnace and to enter in its metal transferring state with its tube holding end into said furnace, the length of said tube being controlled to reach in its metal transferring vertical state adjacent the bottom of said metal holding furnace, while in the non-operative position said length is above the level of the metal in said holding furnace.

References Cited in the tile of this patent UNITED STATES PATENTS 1,983,579 Ennor et al Dec. 11, 1934 1,983,580 Nock Dec. 11, 1934 2,290,083 Webster July 14, 1942 2,301,027 Ennor Nov. 3, 1942 2,458,236 Wolff Jan. 4, 1949 FOREIGN PATENTS 901,093 France Oct. 23, 1944 862,486 Germany Jan. 26, 1953 

